1. Field of the Invention
The present invention relates to steam desuperheaters and, more particularly, to desuperheaters directed to reducing steam temperature by spraying cooling water into a steam flow.
2. Description of the Prior Art
Steam desuperheaters are used for reducing and controlling the temperature of a steam flow. Many devices utilizing steam are designed to operate with a supply of steam at a specified temperature. Where the steam is produced at a temperature higher than that required, a desuperheater can lower the temperature by spraying cooling water into the steam flow upstream of the using device. Once sprayed into the steam flow, the cooling water evaporates, drawing energy from the steam and thereby lowering the steam temperature.
Previously, many conventional desuperheaters simply injected or used nozzles to spray water directly into a flow of steam within a conduit, such as a pipe. Although such devices have generally operated satisfactorily, many have suffered from the disadvantage that they provide insufficient control over the vaporization of the cooling water thereby making it difficult to effectively and accurately control the steam temperature. For example, injected cooling water that does not quickly evaporate may collect at the bottom of the steam pipe and evaporate therefrom in an uncontrolled manner, making precise control of the temperature impossible. Furthermore, unvaporized water can cause erosion and thermal stresses in the pipe, resulting in failure of the pipe conduit.
Various desuperheater designs have been developed to overcome these problems. Some use complex nozzle designs that spray a fine mist of relatively small water droplets. Such nozzles, however, rely on small holes or slots to create the small water droplets and may be prone to fouling or plugging from impurities within the cooling water. Additionally, complex nozzles can be expensive, both to manufacture and to install, with additional costs for individual water supply lines, connections for each nozzle, and labor to install.
Other desuperheater designs attempt to angle the nozzles so as to avoid impinging the walls of the pipe with the spray of cooling water. Such angled nozzle construction may be complex and expensive to manufacture while often being less than fully effective.
Moreover, current desuperheater designs, because of their complexity, must be manufactured to the specification of each individual use, further adding to the costs. Such devices can not easily be customized to meet particular requirements.
In view of the foregoing, it is the object of the present invention to provide a steam desuperheater that more effectively controls the steam temperature in a steam conduit.
Another object is to provide a steam desuperheater nozzle for spraying small water droplets of cooling water into the steam flow in a spray pattern allowing the water to evaporate more effectively.
A further object of the invention is to provide a desuperheater that is less expensive to manufacture and is easily customized for each individual use.
Another object of the invention is to alter the velocity of the steam in the region where cooling water is injected into the steam conduit to permit more effective vaporization of the cooling water.
Still another object is to provide a desuperheater with nozzles that are less prone to fouling or plugging.
Yet another object is to provide a desuperheater with built in nozzle redundancy so that the desuperheater will continue to operate where one of the nozzles becomes inoperative.
A still further object of the invention is to optimize desuperheater performance by allowing proper selection of the number and location of nozzles.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.